Heavy work machines, such as backhoes or excavators, are used on work sites. These machines are generally used for digging and moving dirt. On a number of occasions, there is a need to break up large hard objects before such objects can be moved away. In particular, a work site may contain a variety of materials such as rock, concrete, asphalt, or other hard objects. Backhoes or excavators equipped with commonly mounted implements, such as buckets or blades, may not be able to effectively break up this type of material.
In order to break up such material, the backhoe or excavator may have a powered hammer assembly secured thereto. Typically, the hammer assembly will be powered by either a hydraulic or pneumatic pressure source. During a work or power stroke, high fluid pressure is applied to a first shoulder of a piston, thereby driving the piston in a forward direction. The piston then strikes a hammer, which is driven in the forward direction thereby causing a work tip of the hammer to strike the rock, concrete, asphalt or other hard object to be broken up.
During a return stroke, fluid pressure is applied to a second shoulder of the piston in order to return the piston to its original position. At the end of the return stroke, travel of the piston is restricted or otherwise limited by a contact surface, commonly referred to as a stop. The stop is positioned in a predetermined location in order to properly position the piston for a subsequent work stroke.
When the piston impacts or otherwise contacts the stop, an impact shock is generated. Such an impact shock is transmitted through the powered hammer assembly to the backhoe or excavator. During operation of the powered hammer, the piston is commonly cycled at a rate of up to several hundred work strokes per minute, thereby generating several hundred impact shocks per minute. Hence, during a given work operation a large number of impact shocks are then transmitted through the powered hammer assembly to the backhoe or excavator.
Generation of these impact shocks has several disadvantages associated therewith. For example, the impact shocks are transmitted through the mechanical structure of the backhoe or excavator to a cab which houses an operator, thereby potentially inconveniencing the operator. Moreover, the transmission of the impact shocks through the mechanical structure of the backhoe or excavator, may potentially reduce the useful life of the components associated with the backhoe or excavator.
What is needed therefore is an apparatus and method for decreasing the severity of impact shocks generated by the operation of powered hammers that may be attached to heavy machinery which overcome one or more of the above-mentioned drawbacks.